Screw-driving machine



J. C.' FOY S CREW DRIVING MACHINE Filed July e, 1922 3 sheets-sheet l J.c. FoY

SCREW DRIVING MACHINE Nov. 11, 1924.

3 Sheets-Sheet 2 Filed July 8, 1922 |IIII HH HH Uf l IIIW'" .mailE-mw@JOHN C FOY.

Nov. 1l 1924- rIl.' x

Patenied'Nov. 11, 1924.

UNITED STATES JOHN C. FOY, F OMAHA, NEBRASKA.

SCREW-DRIVING MACHINE.

Application filed July 8,

To (1U lwho/1b it 1111113/ concern.

Be it known that I, JOHN C. For, a citizen of the United States, and aresident of Omaha, in the county of Douglas and State of Nebraska, haveinvented certain new and useful Improvements in Screw-Driving Machines,of which the following is a specification.

My invention relates to portable powerdriven machines for drivingscrews, and it is the general object of my invention to provide ascrew-drivin machine adapted for use in factory assem ling and similarsituations where it is necessary to drive large numbers of screwsrapidly and economically. Moreparticular objects of my invention are toprovide a machine of this character having a magazine for the screws,and adapted to feed the screws automatically from the magazine asrequired for use; to provide a screw-driving mechanism which may beactuated by a portable electric or pneumatic motor; to provide means forautomatically stopping the action of the driving mechanism either whenthe-screw has entered the work a predetermined distance or when apredetermined resistance is offered to the further entry of the screwinto the work; to provide means for guiding and centering the screws asthey are started into the work; to provide a special form of bit forengaging the screw-head and whereby to insure a proper engagementbetween the bit and the slot of the screw-head; to provide means forreadily adapting the mechanism for driving screws of any diameter orlength within the maximum capacity of the machine, and for drivingscrews with any standard form of head; and to provide certain otherdesirable structures and combinations of parts lwhich will be more fullyset forth hereinafter.

Structures embodying my invention are illustrated in the accompanyingdrawings, in which Fig. 1 is a vertical section through the driving andfeed mechanism and a part vof the magazine, Fig. 2 is a detail sectionof the magazine-tube on the line 2-2 of Fig. l, Fig. 3 is a detailsection on the line 3-3 of'Fig. 2, Fig. 4 is a detail horizontal sectionon the line 4-4 of Fig. 1, Fig. 5 is a vertical section similar to Fig.l but showing the parts in the feeding position, Fig. 6 is a side viewof theentire mechanism, including the driving motor, Fig. 7 is a trans-Verse Section 0n the line .--7 of Fg- 6., Fg-

1922. Serial No. 573,654.

8 is a detail side view of one of the jaws of the centering-chuck, Fig.9 is a detail transverse section on the line 9-9 of Fig. 6, Fig. 10 is adetail horizontal section through the clutch-mechanism, the sectionbeing on the line 10-10 of Fig. l1, Fig. 11 is a vertical axial sectionof the clutch and chuckspindle and connecting parts, Fig. 12 is a detailsection on the line 12-12 of Fig. 11, showing the stop-finger en agedwith the rotary clutch-control plate, ig. 13 is a detail transversesection on the line13-13 of Fig. 11, Fig. 14 is a detail section on theline 14-14 of Fig. 13, Fig. l5 is a partial section on the line 15-15 ofFig. 10, Fig. 16 is a detail vertical 'section on the arcuate portion ofthe line 16-16 of Fig. 10, Fig. 17 is a detail side view of theend-portion of a bit for flathead screws, and Fig. 18 is a similar viewshowing the flat side of the bit-lip.

Referring iiI'st to Fig. 6, my screw-driving and feeding mechanism isshown in connection with aA motor of' a type commonly used for portabledrilling machines, wherein the motor-housing 20 has at one end a handle21 and at the opposite end a projecting spindle or shaft 22 which isdriven by the motor and is suitably threaded to receive a drillchuck orthe like. In the structure shown I provide a gear-housin formed inseparable sections 23 and 24 w ich are secured together by bolts 25extending through lugs at the adjoining edges of the sections. The uppersection 23 has a projecting lug or bracket 26 which is secured by ascrew 27 to the motor-housing 20, whereby the gearhousing andmotor-housing are held in such relation that the drive-spindle 22extends into the gear-housing as shown in Fig. 1. On the threadedportion of the drive-spindle 22 is mounted a pinion 28 which meshesoperati'vely with a gear 29 mounted on a shaft 30, the ends of saidshaft being journaled in suitable bearings formed in the housingmembers23 and 24. On the lower portion of the shaft 30 is a pinion 31 whichmeshes operatively with the clutch-gear 32. The clutch-gear is disposedcoaxially with the drive-spindle 22, the ear having an' annularrim-portion and an o set hub-portion which lits revolubly about aportion of the headmember 33 of the chuck-spindle 34. The chuck-spindle34 is secured to the headmember 33 by a transverse pin 35, there beingan intermediate sleeve or bushing 36 through which the 'pin passes, sothat the same spindle 22 is similarly recessed, as showni'n Fig. 1. Thelower end of the chuck-spindle 34 has a taper socket formed therein forreceiving the tapered shank of the bit o r driver 41. A transverse slot42 is provided in the chuck-spindle and housing-tube 37 through which awedge-bar may be inserted for engagi'ng the flattened terminal portion43 of thel bit-shank, for loosening the shank from the taper socket, thearrangement being substantially the same as is commonly used indrill-press-spindles for taper-shank drills. Upon the lower portion ofthe housing-tube 37 .is slidably fitted the feed-tube 44, the lowerportion of said tube 44 extending considerably beyond the lower end ofthe tube 37 and having slidably disposed therein the center-tube 45. Thecenter-tube is held in adjusted relations to the feed-tube by means of acrank-stud 46 which fits in a tubular boss 48 at one side of thefeed-tube, said stud having at the -inner end thereof a short crank-pin47 which extends into a transverseslot in the side of the center-tube,as best shown in Fig. 4. A set-screw 49 in the si'de of the boss 48 isadapted to engage the side of the crank-stud to hold the latter inadjusted positions, and the outer end of the crank-stud is slotted likea screw-head to enable the same to be rotated for adjusting thecenter-tube. At the opposite side of the center-tube there is a smallscrew 50 of which the cylindrical head extends into a longitudinal slot51 in the side of the feedtube, as shown in Fig. 1, said screw 50preventing relative rotation of the members 44 and 45, but permittingrelative longitudinal movement of the same to the vextent of the slot51. The center-tube 45 projects slightly beyond the end of thefeed-tube. and `upon the projecting terminal portion thereof are aplurality of laterally projecting rectangular lugs 52, best shown inFigs. 6 and 7, said lugs serving to support the jaws 53 of thecentering-chuck. The upper portion of each of the jaws 53 fits looselybetween an adjacent pair of the lugs 52, the sides of the jaws havingnotches 54 therein, as best shown in Fig. 8, to receive the lugs. In theouter faces of the jaws, near the lower ends thereof, are roundedgrooves 55 in which is disposed an annular coil springh55 which tends todraw the lower portions of the jaws together,

inner corners and on the lugs 52. At the upper end of the feed-tube 44 acollar 56 is secured by means of screws 57, as shown in Fig. 9, anddownward movement of the feedtube relative to the housin -tube 37 isli'mited by engagement of said co lar with a ring 58 which fits looselyaround the feed-tube at a level slightly below the end of the tube 37.

The ring 58 is fixedly connected with the housing-member 24 by means ofbars 58 which extend up` from the rin past the collar 56 to thegear-housing, as est indicated in Fi'g. 6. The ring 56 also serves toretain the lower end of the screw-magazine 59 ian proper relation to thefeed-tube, said lower end of the magazine being secured to said ring asshown, and the magazine extending diagonally upward therefrom, so as topass through a lug 60 which projects from one end of the housing-member24, as shown. The inner side of the tubular magazine at the lower end isopen, the metal formi'ng the tube at said end being longitudinally slit-and portions thereof opened out to form parallel wings 61, as shown inFig. 2. Said wings 61 extend in to the side of the feedtube, and betweenthem is disposed the tongue or ap 62 which is pivotally mounted at itsupper end, by means of lugs 63 which extend laterally into notches abovethe upper edges of the wings 61, being retained therein by an annularband 63', extending around the magazine as shown. On the side of thefeed-tube adjoining -the magazine there is secured a cam or track-bar 64which is adapted to engage the pivoted tongue 62 and swing the sameoutwardly from the feedtube as shown in Fig. 5, whereby to partiallyclose the lower end of the magazine and prevent the descent of screwstherefrom, except when the feed-tube is raised to its u permost positionas shown in Fig. 1. In t e latter position the tongue is opposite thebeveled lower end-portion of the track-bar, and is thus permitted toswing inwardly and fully open the passage through the magazine. In theside of the feed-tube, below the track-bar and in alinement with themagazine, there is an opening of which all but the uppermost portion iscovered by the pocket or cupmember 65. Said cup-member is secured on theside of the feed-tube in a position such that its upper end adjoins thelower end of the magazine -when the feed-tube is inthe fully retractedposition indicated in Fig. 1. The depth of the cu is such as to enablethe same to contain t e body-portion of the longest screws which are tobe used in the machine, and the width of the cup at its upper end isless than the diameter of the head of the smallest screw to be used. Theopening through the side of the feed-tube adjoining the pocket or cup iscontinued through the center-tube 45, the opening 66 in the lattermember extending to the upper end thereof. On the lower end of thehousing-tube 37- there is finger 67, alined with the opening or slot 66in the center-tube, the

parts being so proportioned that said finger extends down into said slotwhen the feedtube is in the retracted osition. By the describedconstruction, W en the feed-tube is raised or retracted so that thetrack-bar 64 permits the opening. of the pivoted tongue 62, thelowermost screw in the magaz-ine :is

permitted to drop down into the cup 65 until the head of the screwengages the upper edges of the cup. The latter are slightly inclinedinwardly so that the lscrew tends to sli'de in through the opening inthe side of the feed-tube, and through the registering slot 66 in thecenter-tube, but such movement is prevented by the finger 67 until saidfinger is withdrawn from the slot by movement of the feed-tubedownwardly, or outwardly from the housing-members, toward the positionthereof shown in Fig. 5. Upon the withdrawal of the finger 67 from theslot 66 the screw is permitted to pass into the centertube and drop tothe bottom thereof, so that the point thereof enters the fu nnelshapedspace between the jaws 53 of the centeri'ngchuck. The bore or internaldiameter of the center-tube 45 is such as to receive slidably the headsof the screws of largest size to be fed therethrough, and when smallerscrews are to be used'a tubular liner G8 is inserted in the center-tube,being held therein by the screw 50, as shown in Fig. 5, the bore of theliner being suoli as to properly center the heads of the smaller screws,and thus to hold the screws in a vertical position ready for engagementby the driver or bit 41. It will be noted that the body of the bit 41 iscylindrical and of nearly the same diameter as the heads of the screwswith which it is used. For round-head screws, such as are shown in Figs.l and 5, the end of the bit is preferably spherically recessed so as tolit over the screw-heads, and is provided with an inset cross-bar 69 forentering the slot of the screw-head. The use of the full cylindricalbody for the driver-bit insures the proper engagement thereof with thescrewhead when the bit is moved to contact with the screw after the sameis positioned in the center-tube and centering-chuck as shown in Fig. 5.For Hat-head screws the end of the bit is formed as shown in Figs. 17and 18, the body 41, being cylindrical, the lower end thereof beingflat, the inset cross-bar 69 projeeting beyond said flat face so as toenter the slot of the screw-head, and the ends of the cross-bar beingbeveled to conform with the inclined lower face of the screw-head.v Forconvenience in removing the bits from the taper socket in thechuck-spindle, the feed-tube is provided with slots 70, shown in Fig. 6,adapted to register with the slot 42 through the spindle andhousing-tube 87, when the feed-tube is. in the retracted position.

It will be seen that, when a screw has been fed into the center-tube, asdescribed and as shown in Fig. 5, if the bit 41 be rotated and moveddownwardly relative to the feed-tube, the screw-head will be properlyengaged by the bitand the screw thus actuated to enter the work againstwhich the ends of the centering-chuck jaws 53 are held. It will also beseen that the screw will be held in a position perpendicular to thework, by reason of the screw-head being guided by the centertube, whilethe point of the screw is guided by the chuck-jaws 53, the latterexpanding as required to permit the body and head of the screw to passbetween them.

The chuck-spindle 34, and bits carried thereby, are driven from. theclutch-gear 32 through the medium of a friction-clutcharranged betweensaid gear and the headmember 33 of said spindle, it being understoodthat the gear 32 may be either driven continuously or stopped andstarted at the will of the operator by stopping and starting the motorwhich drives the reducinggear train as hereinbefore described. Arcuateclutch-shoes 71 are arranged within the drum formed by the annular rimof the gear 32, as best shown in Fig. 10, each of said clutch-shoesbeing pivotal] y connected at one end to a link 72, and the opposite endof said link being connected pivotally with lugs on the head-member 33.The other end of each clutch-shoe is pivotally connected with a link 73,and the opposite or inner end of said link is connected pivotally withthe hub-portion 74 of the control-plate 75, the hub 74 fitting revolublyabout the lower portion of the sleeve 36, intermediate the head 33 andthe lower side of the housing 24. The links 72 normally extend radiallyof the spindle 34 and are so proportioned that when in said normalposition the adjacent outer faces of the clutch-shoes will lightlyengage the inner face of the drum formed by the gear-rim. The links 73are so proportioned and arranged that when the clutch-shoes are en-vgaged with the` drum said links will extend at an angle to a radius fromthe spindle-axis, or, in other words, so that a line through the pivotalaxes at the inner and outer ends of each link will be tangent'to acircle about the spindle-axis. The direction of rotation of the gear 32is shown by the arrow A in Fig. 10, and, for convenience of descriptionand with reference to said direction of rotation of the parts, the links72 may be considered as connected to the forward ends of springs 77tends to move the clutch-shoes rearwardly and swing the inclined 11nks73toward a radial position, and thus to press y outwardly upon therearward portions of the shoes. Outward movement of the shoes beinglimited by the engagement thereof with the drum, the action of thesprings result-s in the production of a definite frictional Contactbetween the shoes and the dium, suliicient to normally prevent slippagebetween the engaged clutch-surfaces. The driving impulse imparted by thedrum to the shoes is transmitted to the head 33 partly by the links 72and partly through the medium of springs 79 which are arrangedvcircumferentially between the links 72 and arms 80 which extend outfrom said head 33. Said springs 79 are disposed around arcuate rods 81which are fixedly connected witht-he links 72 and pass loosely throughopenings in the arms 80, the ends. of said rods being threaded andprovided with nuts 82 by which the initial compression of the springsmay be adjusted. It will be seen that when the head 33 is being drivenby the clutch connection between the same and the gear 32, thecontrol-plate 75, which is connected with the shoes through the mediumof the links 73 and springs 77, will normally rotate with the otherclutch-parts and maintain the saine relation thereto as when the partsare stationary. If, however, the rotary movement of the plate is checkedor stopped, its relation to the. shoes will be changed in the same wayas if it were to be moved rearwardly, or in a. direction opposite to thearrow' A, while the drum, shoes and head 33 were stationary. It will beapparent that such relative movement of the control-plate will increasethe inclination of the links 73, causing the outer ends of said -linksto swing inwardly and thus tending to pull the rear ends of theclutch-shoes inwardly and disengage them from the drum. The clutch-shoeswill not be completely disengaged from the drum, however, because aftera very slight movement thereof the friction between the faces thereofand the drum will be so reduced that slippage will occur between theengaged faces, and the rotation of the shoes and head 33 will bestopped, while the drum continues to revolve. Thus it will be seen thatthe clutch-mechanism may be rendered inoperative or ineffective indriving the head 33, by first checking, retarding or stopping therotation of the control-plate 75. Stop-posts 76, which eX- tend up fromthe plate 7 5 between the links 72 and 73, serve to limit the rotationof the coutrol-plate relative 'to they other clutchparts. Automaticcont-rol of the clutch mechanism is effected in two ways, bot-h of whichoperate by so connecting the controlplate 75 with the housing-member 24asto prevent rotation of the plate.

On the lower side of the control-plate 75 there lis an annular row ofinclined recesses which form in effect a Series of ratchetteeth 83(shown in Fig. 12) adapted for engagement by fingers 84 extendingthrough openings in the bottom of the housing 24., Said fingers 84 areformed integrally with a collar 85 which is disposed slidalily upon thehousing-tube 37 at the upper end thereof. At one side of the collar 85is a tubular boss 86, the outer end of the opening through said bossbeing closed by a screw 8,7, a ball 88 being disposed in the innerportion of the opening, and the ball being pressed toward the side ofthetube 37 by a small coil spring 89 arranged between the ball and thescrew 87, as shown in Fig. 14. In the side of the tube 37 within thecollar 85 there are two sphere-segmental recesses 90 and 91 into whichthe ball 88 may drop to frictionally retain the collar in definiterelations to the housing. Thus, when the ball is engaged in the upperrecess 90 the collar is held in the raised position shown in Fig. 11, sothat the fingers 84 are in position to engage the ratchet-teeth 83 onthe control-plate and prevent rotation thereof; and when the ball isengaged in the lower recess 91 the collar is held at a lowered positionat which the fingers 84 are disengaged from the coutrol-plate. Rods 92are connected with the collar 85 and extend downwardly therefrom.,passing slidably through lugs 93 on the collar 56, and at their lowerextremities having short outwardly turned port-ions 94 which are.positioned between pairs of lugs 95 extending outwardly from the ring58. Around the upper portions of the rods 92 are disposed coil springs96 of which the normal length is such that the same are slightlycompressed when the feed-tube 44 is retracted to a position such asshown in Figs. 1 and 11, or at which the collar 56 engages the lower endof the collar 85. The. parts are so proportioned that when `thefeed-tube is moved downward or outwardly from the housing to thescrew-feeding position shown in Fig. 5, the end-portions 94 of the rods92 are engaged by fingers 97 on the lugs 93, and the rods andcollar 85thus pulled outwardly from the housing, whereby to disengage the fingers84 from the control-plate 75. The clutch mechanism is thus freed so thatactuation of the spindle 34 is started, providing, of course, that theclutchgear 32 is being driven by the motor. In the lowered position ofthe lcollar 85 the ball 88 is engaged in the recess 91, which retainssaid collar in the clutch-releasing position until the same is forciblymoved upward again by the engagenu-.nt of the collar 56 therewith. Suchengagement occurs as the feed-tube approaches the fully retractedposition shown in Fig. 1, at which the driving of the screw is nearlycompleted. After the application to the collar of sufiicient force toldislodge, the ball 88 from the recess 91, so that the upward movement ofthe collar is thereby started, the springs 96 expand and cause a rapidcompletion of the upward movement, at the end of which the ball entersthe recess 90. rfhe rapid movement of the collar to the clutchengagingposition is thus effected independently of the rate at which thefeed-tube is being moved ujnvardly relative to the housing-tube 37, andinsures a complete en` gagement of the lingers 84 with the ratchetteeth83 on the control-plate 75, without preliminary dragging or partialengagement between said fingers and teeth.

The group of mechanism last above described comprises the first of thetwo means for automatically controlling the clutch mechanism, and itwill be seen that the driving of the chuck-spindle and driver-bit willbe stopped when a screw has been driven into the work a predetermineddistance. The exact extent to which the screw will enter the work beforethe driving connection is broken, may be varied within the requiredlimits by adjusting the position of the center-tube 45 relative to thefeed-tube, by means of the crank-stud 46 as before described. Thus, byraising the center-tube, the total length from the upper end of thefeed-tube to the ends of the centering-chuck jaws 53, which rest againstthe work, will be reduced with the result that the end of the bitengaging the screw-head will be closer to the work before thecontrol-collar 85 is engaged and moved to effect the throwout of theclutch connection. Extending or lowering the center-tube relative to thefeedtube will cause an opposite eect, and the screw will be driven lessdeeply into the Work ble-fore the throw-o-ut of the driving connection.

On the control-plate 75, and positioned normally beneath the outer endsof the arms 80, there are flat springs 98 which are secured to the plateat one end, and at the other end carry the pawl-blocks 99 which eXtenddownward through openings in the plate, as shown in Fig. 16. Saidsprings 98 normally hold the pawl-blocks in the raised positionrepresented in said figure, but if the free ends of the springs bepressed downwardly the pawl-blocks are caused to project beneath theplate to engage ratchet-teeth 100 which are formed on the adjacentportion of the housing 24 by an annular series of inclined recesses,similar to the recesses which form the teeth 83 on the control-plate. Onthe sistance offered to rotation of the driver-bity is greater than apredetermined amount. As previously noted, the driving impulse receivedfrom the gear 32 is transmitted from the clutch-shoes through the links72, springs 7 9 and arms 80, to the head-member 33. The initial ornormal compression of the springs 79 is so adjusted that there will bebut little additional compression of said springs under the normaldriving-load, or by the transmission through the clutchmechanism of theforce necessary to drive the screw into the work. Should the screw meetwith excessive resistance, however, the springs 79 will be compressedand the forward ends of the clutch-shoes will approach the arms 80,thereby engaging the upper arms of the angle-levers 101, pressing thesame toward the arms 80 and thus moving the lower arms of saidangle-levers downwardly so that they will press upon the springs 98.Then, after said springs have been pressed downward slightly, thepawlblocks 99 will engage the teeth 100 on the housing, thusinterconnecting the controlplate and housing and causing the throwout ofthe clutch-mechanism.

The last described, or second, means for stopping rotation of thecontrol-plate serves as a safe-guard to prevent the application to ascrew of suiiicient force to break the head thereof or to injure thedriver-bit. The said controlling or stopping means is also ico usefulwhen screws are to be driven so that the heads thereof enter acounter-bore in the work. For such conditions, there is used a bit ofgreater length than that usually employed, so ythat when theI otherparts are in the positions shown in Fig. 1 the lower end of the bit willextend through the center-chuck jaws far enough to enable it to enterthe eounterbore and engage the head of the screw therein without causingthe jaws 53 to engage the work and thus raise the feed-tube far enoughto actuate the control-collar 85. The throw-out of the clutch mechanismis then effected solely by the increased resistance offered when thescrew has been fully driven, so that the head thereof is engaged withthe worrk.

Now, having described mv invention, what I claim and desire to secure byLetters Pat.- ent is:

1. In a machine of the class described, a motor, a spindle, a clutch forconnecting the spindle with the motor, reciprocating screwguiding means,clutch controlling mechanism having a member movable into and out ofengagement with the clutch, and

guiding means, clutch controlling mechanism having a member movable intoand out of engagement with the clutch, means for connecting' the Saidmember with the screw-guiding means for actuating the member at the endsof the movements of the screw-guiding means to move the said memberalternately in opposite directions into and out of engagement with theclutch, and a spring arranged to be compressed to produce a rapidmovement of the said member towards the clutch.

3. In a machine of the class described, a motor, a spindle, a clutch forconnecting the spindle with the motor, reciprocating screwguiding means,clutch controlling mechanism having a slidable member, a. rod connectedwith the slidable member and having an outer terminal portion arrangedto be engaged by the screw-guiding means to move the member away fromthe clutch, said member being directly engaged by the screwguiding meansto move it towards the clutch. j

,4. In -a machine of the class described, a motor, a spindle, a clutchfor connecting the spindle with the motor, reciprocating screwguidingmeans, clutch controlling mechanism having a slidable member, a rodconnected with the slidable member and having an outer terminal portionarranged to be engaged by the screw-guiding means to move the memberaway from the clutch, said member being directly engaged by thescrew-guiding means to move it towards the clutch, and a spring disposedon the rod and arranged to be compressed to cause a rapid movement ofthe member in engaging the same with the clutch.

5. In a machine of the class described, a motor, a spindle, a clutch forconnecting the spindle with the motor, reciprocatory screwguiding means,a sliding collar provided with fingers for engaging the clutch, rodssecured to the collar and having projecting terminal portions arrangedto be engaged by the screw-guiding means-to move the collar away fromthe clutch, said,y collar being directly engaged by the screw-guidingmeans to move it towardsthe clutch, and springs disposed on the rods andarranged to be compressed to cause a rapid movement of the collartowards the clutch.

6. In a machine ofthe class described, a

motor, a spindle, a clutch for connecting the spindle with the motor,reciprocating screwguiding means having a collar provided withprojecting lugs, a clutch engaging collar, rods connected with the-sameand extending through the collar of the screw-guiding means, and havingprojecting terminal portions arranged to be engaged by the lugs of thescrew-guiding means, and a relatively fixed collar provided with meansfor guiding the rods.

7. In a machine oi the class described, a motor, a spindle, a clutch forconnecting the spindle with the motor, screw-guiding means, clutchcontrolling mechanism including a member movable into and out ofengagement with the clutch and actuated by the 'screw-guiding means, andmeans for locking the slidable member in and out of engagement with theclutch.

8. In a machine of the class described, a motor, a spindle, a clutch forconncting the spindle with the motor screW-guidin g means,

clutch controlling mechanism including a.

member movable into and out of engagement with the clutch and actuatedby the screwguiding means, and yieldable means for automatically lockingthe slidable member in and out of engagement with the clutch.

9. In a machine of the class described, a motor, a spindle, a clutchhaving a relatively movable control plate adapted to be actuated toconnect the clutch with and disconnect the clutch from the spindle andprovided with teeth, screw-guiding means, and a member actuated by thescrew-guiding means and having a finger carried into and out ofengagement with the control plate to operate the clutch.

10. In a machine of the class described, a motor, a spindle, a clutchhaving a relatively movable control plate adapted to be actuated toconnect the clutch with and disconnect it from the spindle and providedwith an annular series of teeth, work-engaging means, and a slidablemember actuated' by the work-engaging means and having a finger movableinto and out of engagement with the said teeth.

11. In a machine of the class described, a

relatively fixed tubular member, a spindle operating in the tubularmember, -a magazine consisting of an inclined tube having its lower endlocated adjacent to the tubular member, a feed tube slidable on thetubular -ing a portion of its travel.

13. In a machine of the class described, a relatively fixed tubularmember, a spindle operating in the tubular member, a magazine supportedupon the. tubular member, a feed tube slidable on the tubular member forfeeding screws from the magazine to the spindle, said feed tube beingprovided with means for closing the magazine and for permitting the sameto open, said latter means including a pivoted plate, and a cam trackcarried by the feed tube and arranged to hold the pivoted plate in itsclosed position during a portion of the travel of the said feed tube.

14. In a machine of the class described, a tubular member, a spindleoperating in the tubular member, a magazine, a feed tube slidable on thetubular member and provided with a screw receiving pocket carried to andfrom the magazine by the feed tube, said pocket being open at the topand inner side, and a linger extending from the tubular member andarranged to close the inner side of the pocket during a portion of thetravel of the 'feed tube.

' 15. In a machine of the class described, a tubular member, a spindleoperating in the tubular member, a feed tube slidable on the tubularmember and provided with an opening adapted to be carried beyond thespin- (lle, a magazine, a screw receiving pocket mounted on the feedtube at the opening thereof and carried to and from the magazine by thesaid feed tube for feeding screws to the spindle, and a linger on thetubular member for stopping the opening to the feed tube when the pocketadjoins the magazine.

16. In a machine of the class described, a tubular member, a spindleoperating in the tubular member, a feed tube slidable on the tubularmember and provided at one side with an opening, a maga-zine, a pocketcarried by the feed tube to and from the said magazine, said pocketbeing open at its inner side and having an inclined upper edge forcausing the screws to slide inwardly, and means on the tubular memberfor holding the screws against such inward movement when the pocket adjoins the magazine.

17. In a machine of the class described, a tubular member, a spindleoperating in the tubular member, a feed tube slidable on the tubularmember and provided at one side with an opening, a magazine, a pocketcarried by the feed tube to and from the said magazine, said pocketbeing open at its inner side and having an inclined .upper edge forcansing the screws to slide inwardly, and a ixed finger extendinglongitudinally of the feed tube and arranged to hold the screws againstinward movement during a portion of the travel of the feed tube.

18. In a machine of the class described, a tubular member, a spindleoperating in the tubular member, a magazine consisting of an inclinedtube provided at its lower end with a pivoted plate arranged to swinginwardly and outwardly to open and close the magazine, a feed tubeslidable on the tubular member and provided with a pocket carried to andfrom the magazine by the feed tube, and a cam track also carried by thefeed tube and arranged to hold the pivoted plate in its closed positionduring a portion of the travel of the feed tube and permitting thepivoted plate to open during another portion of the travel of the feedtube.

19. In a machine of the class described, a moto-r, a spindle, a clutchfor connecting the spindle with the motor and for disconnecting ittherefrom, reciprocating feeding means having a slidable feed tube,means operated byfthe slidable feed tube lfor controlling the .blutch,and means for varying the effective length of the feed tube and theconsequent periods of operation of the clutch.

20. In a machine of the class described, a motor, a spindle, a clutchfor connecting the spindle with the motor and for disconnecting ittherefrom, reciprocating feeding means having a slidable feed tube,meansv operated by the slidable 'feed tube for controlling the clutch, aliner sleeve arranged within the feed tube for varying the diameter a-ndlength of the same, and means for adjusting the liner sleeve and forsecuring the same in its adjustment.

21. In a screw-driving mechanism, a rotary driver-bit, a tubularscrew-magazine mounted in fixed relation to the axis of said driver-bit,a feed-tube disposed eoaxially with the bit and movable longitudinallyfrom a retracted position at which the bit extends through the same toanextended position at which the bit is withdrawn therein, a pocket-membercarried upon said feed-tube, there being a feed-passage from saidpocketmember through the side of the tube into the bore thereof, saidpocket-member having an open end extending adjacent to the. end of themagazine-tube when the feed-tube is in retracted position, means forpreventing egress of screws from the magazine-tube, said means beingreleasable by retraction of the feed-tube, whereby to deliver a screwinto the pocket-member when the feed-tube is moved to retractedposition, and a member held in fixed longitudinal relation to the llUCFI

bit and movable into the feed--passage between the pocket-member and thebore of the tube when the latter is in retracted position, Said memberbeing' Withdrawn from said passage to enable delivery of a screw fromthe pocket to the bore bf the tube when the latter is in its extendedposition.

22. In a machine of the class described, a mot-0r, aspndle,a clutch forconnecting the motor and spindle, Said clutch havinga eontrol platemounted thereon and normally rotating therewith, said control platebeing arranged to throw out the clutch When rotatation thereof and throwout the clutch, a

fixed member, and means on the control plate engageable with Said fixedmember to -cheek rotation-0f said plate, said means arranged to beactuated when the spindle meets with predetermined resistance.

JOHN C. FOY.

